The enactment of portability is, perhaps, the most important recent change in the estate tax law. Under Section 2010(c), a dece­dent’s executor can elect on a time­ly filed estate tax return to transfer the deceased spousal unused exclusion (DSUE) amount (the unused unified credit) to the surviving spouse. Portability has dramatically altered modern estate planning for many clients, allowing them to avoid the use of non­ marital trusts in a substantial number of instances.